add test on iterators (see #394)

transpiler/src/test/java/org/jsweet/test/transpiler/NativeStructuresTests.java

@@ -15,6 +15,7 @@ import source.nativestructures.ExtendsJDKAnonymous;
 import source.nativestructures.ExtendsJDKInterface;
 import source.nativestructures.ExtendsJDKRegular;
 import source.nativestructures.Input;
+import source.nativestructures.Iterators;
 import source.nativestructures.Maps;
 import source.nativestructures.NativeArrays;
 import source.nativestructures.NativeStringBuilder;
@@ -198,5 +199,11 @@ public class NativeStructuresTests extends AbstractTest {
 		}, getSourceFile(ExtendsJDKAnonymous.class));
 	}
 
+	@Test
+	public void testIterators() {
+		eval(ModuleKind.none, (logHandler, result) -> {
+			logHandler.assertNoProblems();
+		}, getSourceFile(Iterators.class));
+	}
 	
 }

transpiler/src/test/java/source/nativestructures/Iterators.java

@@ -0,0 +1,52 @@
+package source.nativestructures;
+
+import java.util.Iterator;
+
+public class Iterators {
+
+	public static void main(String[] args) {
+		Range r = new Range(10, 20);
+		Iterator<Integer> it = r.iterator();
+		int j = 10;
+		while (it.hasNext()) {
+			int i = it.next();
+			assert i == j++;
+		}
+		assert j == 20;
+	}
+
+}
+
+class Range implements Iterable<Integer> {
+
+	private int start;
+	private int end;
+	private int at;
+
+	public Range(int start, int end) {
+		this.start = start;
+		this.end = end;
+		at = start;
+	}
+
+	public Iterator<Integer> iterator() {
+		return new RangeIterator();
+	}
+
+	private class RangeIterator implements Iterator<Integer> {
+
+		public boolean hasNext() {
+			return at < end;
+		}
+
+		public Integer next() {
+			int next = at;
+			at += 1;
+			return next;
+		}
+
+		public void remove() {
+		}
+	}
+
+}